The packaging of large heavy articles presents a number of problems for manufacturers. Residential and commercial cast iron bathtubs are one type of such articles that require special attention for packaging for shipping, storing, and handling. Cast iron bathtubs are heavy, typically weighing up to 400 pounds, and are easily subject to damage if mishandled. Cast iron tubs have porcelain finish surfaces which may be easily scratched, cracked, or chipped if the tub or its container is mishandled. Cracks and chips allow water to contact the cast iron substructure of the tub and can result in discoloration due to rusting. This type of damage is not easily repaired either at the factory or at the receiving destination. Competition for sales among manufacturers and low profit margins associated with cast iron tubs require manufacturers to give particular attention to the packaging and to the tubs held in the packaging. Bathtubs are typically closely inspected at the manufacturing facility before packaging so that tubs with surface defects are not shipped to customers. Reputation for quality products accordingly depends on the tubs being delivered to destinations without defects created during shipping, storage, or handling.
The packaging, or containers, for cast iron tubs must meet several competing needs. Containers typically are not a value-added feature for articles, and the costs are directly added to the costs of the articles. Containers should therefore be made of relatively low cost materials. Such materials, however, may not be sufficient for meeting the structural and protective needs of containers for heavy articles.
The containers for cast iron tubs must have sufficient structural strength to contain the heavy cast iron tub while being transported. The containers must withstand the vibrations typically associated with motor freight and rail shipment. These transportation systems incur sudden starts and stops, rough road conditions, and handling forces that subject the containers to extreme stresses. The containers must absorb such stresses without causing damage to the tubs. Handling tools such as clamp trucks, forklift trucks, and dollies are typically used to move the contained products between storage and shipping vehicles. These grip, pickup, and move containers forcefully, and containers may be pierced, pinched or broken during handling. A broken container risks damage to the contents.
Bathtubs are transported with the tubs positioned either vertically or positioned horizontally. In the vertical position, the tubs are positioned in containers that stand on one end. The shape and weight distribution of the tub prevents it from standing unsupported on the end. Therefore the container itself must support and restrain the tub from tipping over during handling, storage, and shipping. In the horizontal position, the tub is typically packaged upside down. Shipping and handling tubs horizontally may create abrasion damage to the rim surface of the tub. The cleating for the container must have sufficient strength and be sufficiently fixed to the walls of the containers so as to not break or pull loose in response to the forces encountered during handling, stacking and warehousing. Cast iron tubs are often handled and shipped vertically due to the improved space utilization and reduction of abrasion of the porcelain rim surface of the tub.
Containers for cast iron tubs must also have sufficient compression strength so that the containers may be stacked one above another to have more efficient utilization of warehouse storage space. Often containers of bathtubs are stacked four or five units high. The cost of space for finished-goods warehousing is thereby minimized as higher ceiling buildings hold more product per square foot of floor space than if the goods are not stackable. Such stacking conditions, however, may impose loads of up to 1600 pounds of force on the lowermost unit in the stack.
The container for packaging heavy consumer goods such as bathtubs therefore faces the competing requirements of low cost materials yet relatively high structural strength. Presently, cast iron tubs are packaged in a wirebound container. Thin wooden slats are joined to thicker wood cleats by staples to form open-sided panels for a crate. The panels are connected together by bailing wire which is stapled to the wood cleats. Such wirebound containers have adequate strength for handling and shipping, but have several disadvantages which limit their practical use presently and in the future. One known manufacturer produces porcelain bathtubs at a rate of about 480 bathtubs per eight hour shift. The shipping containers must be simple and easily set up for insertion of the tub. The stiff wires make these wirebound containers awkward to handle when packaging a finished bathtub. Difficulty in assembling the containers and in packaging bathtubs in assembled containers can result in production line slow down and loss of production.
The nature of the wood and wire materials makes disposal of the wirebound containers difficult after use. The wire is rigidly attached to the wood, and separating the wire from the wood is laborious and time consuming. Typically, landfills are the only disposal method for such wire bound crates. There are a number of environmental factors which limit the availability of landfills for disposing of wirebound containers, including the shortage of available landfill space, pressures from government and environmental groups regarding use of landfills, and the associated increasing costs of disposing of materials in landfills. The wirebound crates also may create quality problems for cast iron tubs. The crates typically are open which allow grit and dust to settle on the surface of the tub. Objects can fall or be pushed against the tub surface. The grit and objects can result in damage to the porcelain finish, and at the least, cause an unsightly appearance of the tub at the showroom or at installation in a bathroom. Surface repairs are difficult and in practice may result in a more unsightly appearance for the bathtub.
There are other factors that limit the use of these wirebound containers. Printing of information is impractical on the wood surfaces of the wirebound containers. The limited surface area offers little, if any, potential for advertising or graphics to attract consumers to the product. The use of wirebound containers may also pose hazards for persons handling the containers due to the potential of the wood for splinters and the wire for staple pricks and cuts. Recently the supply of container-grade wood is being reduced, and this increases the cost of such wood. Further, the number of manufacturers of such wirebound containers is declining. These factors result in difficulties with supply and increased costs for manufacturers of products shipped in wirebound containers.
Accordingly, there is a need in the art for a low cost, high strength container for holding and protecting cast iron tubs during shipping, storage and handling.